This invention relates to spectacles and more particularly to metallic frame spectacles.
Metal frames have long been in use and still offer many advantages over frames made of plastic. Plastic frames for instance have various limitations including the fact that they are subject to degradation with age and concomitant cracking, they tend to lose their shape, particularly when subjected to elevated temperatures and there are fewer options for design variations with such frames. On the other hand, metal frames have several characteristics which must be dealt with to make them suitable for use. Means must be provided so that the frame fits comfortably on the wearer's nose. Since metal is a good thermal conductor the frame would feel uncomfortable in temperature extremes, hot or cold, so a nose pad assembly having a surface formed of thermal insulating material should be provided to interface between the frame and the wearer. Another problem posed by metallic frames relates to the fact that since the eye wire is split in order to accomodate a lens the frame is weakened in the vicinity of the slit and is subject to twisting movement and possible chipping or breaking of the lens. Additionally, the slit detracts from the aesthetic appeal of the frames.
These problems can be handled to some extent when the metal employed for the frames is conducive to conventional soldering techniques, such as nickel silver frames. With regard to the aesthetic detraction of the slit a cosmetic plaque can be soldered to the eye wire above or below the slit and extend over the slit area to thereby conceal it; however, the frame is still in a weakened condition due to the slit. In respect to the nose pad assembly, metal posts mounting suitable plastic pads can be soldered directly to the bridge area of the frame.
However, many frames are composed of material such as aluminum, which is not readily solderable. From a market standpoint acceptance of such frames has been limited due to the inability of prior art approaches to deal with these problems even though frames made of aluminum or the like offer other advantages such as lightness in weight, high strength and design versatility, that is, the frame can be provided with many different finishes and colors.